Little is certain about this year's recipe will be, except that making a short film in 48 hours is sure to put a few brains to the test – as will the sleep deprivation.

Wellington team Noise and Pictures, headed by director Giles McNeill, were the national winners of the V 48Hours Film Festival last year with their zombie-themed Brains! – a love story that had the cinema audience cheering for the undead.

The festival is back this weekend – now called the Rialto Channel 48Hours Furious Film-Making Challenge – with a record 229 Wellington teams taking part. More than 800 are participating nationwide.

The team behind Noise and Pictures are right now somewhere in Wellington, all things going to plan, shooting a short film written from scratch since 7pm last night. They will hand in a finished, edited copy of the film before 7pm tomorrow.

"Every year we think it can't possibly grow. Every year more and more people come out of the woodwork."

Last night, teams met at the Mac's function centre on the Wellington waterfront. Each was given a genre in which to create a film, plus a few ingredients that had to be included.

This year, they are the line "Did you hear that?"; a character called Vic Meyer; an insomniac; and a card that has to be used as a prop.

Wellington actor Aidan Grealish, a disturbingly sympathetic zombie in last year's Brains!, said that when the lockdown ends each year "they open the doors and everyone just bolts and heads to their HQs".

For Noise and Pictures, each person is assigned a role. "Usually we will nut it out for a couple of hours. Giles runs quite a tight ship."

While most of the crew head home for a sleep, a small team of writers work on a script, with the rest getting up before dawn on the Saturday, when they try to finish all filming.

Sunday is for editing, then dropping off the final copy for the 7pm deadline.

While Noise and Pictures tends to get its finished film in with plenty of time, others push it to the limit.

"It's gridlock," Grealish said. "There are people on scooters, 10-speeds, taxis, doing whatever they can to get there. There are kids in the car park over their laptops hoping it downloads."

McNeill reckons that, in an average year, he would get at most two hours' sleep on the Friday night, then four hours on Saturday.

"The great thing about the [contest] is it is only 48 hours. If you can't get through it, you shouldn't be doing it at all. You can do anything for 48 hours.